We wish to examine the expression of an antibody that does not have significant binding for DNA in nonautoimmune and autoimmune mice and then to study the progeny of this antibody that arise through somatic mutation in both types of mice. We have selected an antibody that does not bind dsDNA but which in autoimmune NABWF1 mice acquires increased binding for dsDNA as it undergoes somatic mutation. We will examine the expression of the heavy and light chain of this antibody individually and together in NZW mice and examine the somatically mutated products of this antibody in this nonautoimmune strain. We will then mate NZW expressing both H and L to NZB and follow the expression and somatic mutation of the antibody in the autoimmune F1 animals.